PEA FAMILY 493 



truncate or emarginate, 1-1.5 cm. long, strigose beneath, glabrous above; raceme 

 short; calyx strigose, sometimes with dark hairs; tube 7-8 mm. long; teeth sub- 

 ulate, 2 mm. long; corolla 2 cm. long; pod rounded-ellipsoid, over 1.5-2 cm. in 

 diameter. A. succulentus Richards. A. prunifer Rydb. Plains and hills: Sask. 

 Colo. Mont. Plain Submont. My-Je. 



22. ASTRAGALUS (Tourn.) L. Loco WEED, MILK VETCH. 



Perennial or annual herbs. Leaves alternate, odd-pinnate. Flowers per- 

 fect, racemose. Calyx campanulate to cylindric, 5-lobed; lobes usually dis- 

 tinctly unequal. Corolla purplish or white, or rarely ochroleucous; banner with 

 an erect blade, usually longer than the wings and the keel; keel not beaked, its 

 petals wholly united. Stamens 10; filaments diadelphous; anthers alike. Pods 

 ovoid to oblong, leathery or woody, turgid, 2-celled, dehiscent; partition formed 

 by the intruded lower suture. Seeds usualh many. 



Plants cespitose. subscapose, villous-pubescent ; pods sulcate on both sutures. 



I. MOLLISSIMI. 

 Plants with elongate leafy stems. 



Pods not sulcate or slightly so on the lower suture, round or nearly so in cross-section. 



II. ULIGINOSI. 

 Pod deeply sulcate on the lower suture, cordate or triangular in cross-section. 



Leaves and stems strigose or glabrate; pods several-seeded. III. HYPOGLOTTIDES. 

 Leaves and stem villous; oods few-seeded. IV. SPALDINGIANI. 



I. MOLLISSIMI. 



Pod glabrous, deeply sulcate. 1. A. mollissimus. 

 Pod villous, slightly sulcate. 



Calyx densely villous; leaflets 6-12 pairs. 



Pods perfectly 2-celled; raceme elongate. 2. A. Bigelovii. 



The cells of the pod confluent at the apex; raceme short. 3. A. Thompsonae. 



Calyx sparingly nigrescent; leaflets 36 pairs. 4. A. anisus. 



II. ULIGINOSI. 

 Pod straight or nearly so. 



Calyx-tube 46 mm. long, 3^4 mm. wide. 



Bracts linear-lanceolate, long-attenuate, the lower almost as long as the calyces; 

 calyx-teeth all narrow, subulate, fully half as long as the tube; pod glabrous. 



5. A. canadensis. 



Bracts ovate to lanceolate, scarcely half as long as the calyces ; calyx-teeth short, 

 less than half as long as the tube, the upper broader; pod more or less 

 hairy (except sometimes in the first). 



Upper calyx-teeth only slightly broader than the lower; bracts lanceolate. 

 Calyx not black-hairy; pod not sulcate. 6. A. oreophilus. 



Calyx more or less black-hairy; pods somewhat sulcate on the lower suture. 



7. A. Mortoni. 

 Upper calyx-teeth about twice as broad as the lower, broadly triangular at 



the base; pod not sulcate. 8. A. spicatus. 



Calyx-tube about 3 mm. long, less than 2 mm. wide. 9. A. ur sinus. 



Pod decidedly arcuate. 18. A. palans. 



III. HYPOGLOTTIDES. 

 Pod with appressed gray or black pubescence. 



Calyx-teeth short and broad; corolla purple. 10. A. terminalis. 



Calyx-teeth subulate. 



Corolla purple or pink, seldom white; calyx-teeth much shorter than the tube. 



11. A. striatus. 



Corolla sulphur-yellow, white, or pinkish; calyx-teeth almost equalling the tube. 

 Leaflets elliptic, appressed-pubescent. 12. A. sulphur escens. 



Leaflets broadly obovate; pubescence looser. 13. A. oreganus. 



Pod villous with long spreading hairs. 



Corolla ochroleucous; bracts broadly spatulate to linear, obtuse. 



14. A. virgultulus. 

 Corolla purple; bracts ovate-lanceolate or oblong-lanceolate, often acutish. 



Calyx black-hairy; teeth decidedly shorter than the tube. 15. A. goniatus. 

 Calyx not black-hairy; teeth about equalling the tube. 16. A. agrestis. 



IV. SPALDINGIANI. 

 One species. 17. A. Spaldingii. 



1. A. mollissimus Torr. Stems less than 1 dm. long, decumbent, densely 

 villous; leaves mostly basal; leaflets 23-29, obovate to oval, 6-25 mm. long, 

 silky- villous ; racemes short; calyx-tube cylindric, silky, 7-9 mm. long; teeth 

 subulate, about 3 mm. long; corolla bright purple, about 18 mm. long; pod cyl- 

 indric, 2 cm. long, curved upwards. Prairies and plains: Neb. Tex. N.M. 

 Wyo. (? Mont.). Plain. My-Jl. 



